In the USA, the incidence of esophageal adenocarcinoma has risen more than 350% since 1974 while long-term survival rates have remained at 10-15%. Current staging methods are inadequate for predicting survival in this disease, as evidenced by the fact that even patients with early stage, potentially resectable tumors frequently recur and die. Since treatment options are based on pathologic stage, clinicians need improved staging methods to assist in appropriate treatment planning for these patients. Our previously published reports indicate that disease recurrence and poor survival in esophageal cancer patients may be predicted, in part, by the presence of occult metastases to lymph nodes. Recently however, Beer et al. reported in Nature Medicine that gene expression patterns in primary tumors can predict outcome in stage I lung cancer patients. In addition, three new reports in Nature Genetics and The Lancet and Cancer Cell demonstrate that the propensity to metastasize may actually be encoded in the gene expression patterns of primary tumors. Furthermore, the Lancet study by Huang et al. identified separate gene sets that seem to predict lymph node metastasis and overall recurrence in breast cancer patients. These interrelated events would thus appear to be the result of distinct biological processes that can be detected by analysis of the primary tumor. It is our hypothesis that gene expression patterns in the primary tumor determine metastatic potential and probability of survival for patients with esophageal adenocarcinoma. Subsequently, we believe that microarray analysis of esophageal tumors will allow us to identify sets of genes that correlate with both metastasis and survival. Given the correlation between lymph node status and survival in esophageal cancer, we also hypothesize that gene expression analysis and occult disease detection approaches will identify overlapping sets of patients at high risk for recurrence. In this proposal, we intend to explore the relationship between data obtained from microarray analysis of the primary tumors and analysis of occult lymph node involvement. We believe that the combination of this comprehensive molecular staging will allow us to significantly improve upon the current staging of esophageal adenocarcinoma. In addition, we believe that this research will answer some very interesting questions about tumor biology and metastasis in esophageal cancer.